Texas Instruments CD74HCT154EN

Overview

CD74HCT154EN from Texas Instruments is a 4-to-16-line decoder/demultiplexer with dual enable inputs (E1, E2), operating at 4.5V–5.5V, supporting LSTTL-compatible logic levels (VIL ≤ 0.8V, VIH ≥ 2.0V), and rated for -55°C to +125°C industrial/military temperature range. It drives up to 15 LSTTL loads and delivers 35ns typical propagation delay (CL = 50pF, VCC = 4.5V) in address-to-output paths, used in address decoding for memory expansion and I/O port selection.

For engineers reviewing the CD74HCT154EN datasheet, CD74HCT154EN pinout, CD74HCT154EN application, or CD74HCT154EN equivalent, this page provides verified functional identity, validated 24-pin PDIP package mapping, confirmed HCT-family electrical behavior, truth-table-defined demux/decoder operation, and real-world substitution guidance - all grounded in TI's SCHS152D datasheet and official ordering documentation.

Technical Context

The CD74HCT154EN implements active-low 4-bit binary decoding: four address inputs (A0–A3) select one of sixteen complementary outputs (Y0–Y15), while both enables (E1, E2) must be low for valid output assertion. Its architecture supports cascading via enable chaining and demultiplexing by routing data through E1/E2 with the other held low.

It uses CMOS silicon with TTL-compatible input thresholds and rail-to-rail output swing, delivering 4.4V VOH (min) and 0.1V VOL (max) under CMOS load at VCC = 4.5V, with input leakage ≤ ±1µA and quiescent ICC ≤ 160µA across full temperature range. Propagation delays are balanced between address and enable paths (tPLH/tPHL ≤ 53ns max at -55°C to +125°C).

Key Specifications

Pinout & Package

CD74HCT154EN is supplied in a 24-lead plastic dual in-line package (PDIP), 0.300-inch body width (package code "EN"), with standard through-hole mounting and JEDEC MO-091AC outline.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-to-16 decoder/demultiplexer applications.

Compared with SN74HCT154N and CD74HC154EN, the CD74HCT154EN uniquely combines guaranteed -55°C to +125°C operation with native LSTTL input compatibility - making it the sole choice for ruggedized systems requiring drop-in replacement of legacy TTL decoders without redesign.

Availability

CD74HCT154EN is available at Aetrix Electronics and suitable for memory address decoding, I/O port expansion, industrial control logic, and military/aerospace subsystem enable applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HCT154EN includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and aerospace qualification coverage.

The CD74HCT154EN belongs to TI's CD74HCT high-speed CMOS logic family, engineered specifically for seamless integration into legacy 5V TTL systems requiring extended temperature resilience and low-power CMOS efficiency.

FAQ

What is the maximum operating temperature of the CD74HCT154EN?

The CD74HCT154EN is rated for continuous operation from -55°C to +125°C, per its official datasheet (SCHS152D). This specification is validated across all electrical parameters including propagation delay, output drive, and input thresholds - making it suitable for under-hood automotive, downhole oil/gas, and military platform applications where thermal extremes are routine. The CD74HCT154EN maintains full functionality without derating across this full range.

Does the CD74HCT154EN support cascading with other decoders?

Yes, the CD74HCT154EN supports cascading via its dual active-low enable inputs (E1 and E2). One CD74HCT154EN can serve as a higher-order selector whose outputs drive the enables of multiple lower-level CD74HCT154EN devices - enabling 5-to-32, 6-to-64, or larger decoding trees. This architecture is explicitly documented in the functional description and truth table of the CD74HCT154EN datasheet.

Is the CD74HCT154EN pin-compatible with the SN74HCT154N?

Yes, the CD74HCT154EN and SN74HCT154N share identical 24-pin PDIP footprints, pin assignments, and logic functions. However, they differ in temperature qualification: CD74HCT154EN is rated for -55°C to +125°C, while SN74HCT154N is limited to -40°C to +85°C. Electrical timing and drive specs are otherwise matched, allowing direct PCB reuse where extended temperature is not required.

What logic family does the CD74HCT154EN belong to, and why does it matter?

The CD74HCT154EN belongs to the HCT (High-speed CMOS with TTL-compatible inputs) family. This means it uses CMOS transistors for low power and high noise immunity, yet accepts standard TTL voltage thresholds (VIL ≤ 0.8V, VIH ≥ 2.0V) - enabling direct connection to legacy 74LS, 74ALS, and other 5V TTL outputs without level shifters. This hybrid behavior is central to the CD74HCT154EN's role in upgrading aging systems.

Can the CD74HCT154EN be used as a demultiplexer?

Yes, the CD74HCT154EN functions as a 1-to-16 demultiplexer when one enable (e.g., E1) is used as the data input and the other (E2) is held low, while A0–A3 select the destination output Y0–Y15. This mode is explicitly described in the datasheet's "Demultiplexing Function" section and confirmed by the truth table - where E1 and E2 are treated as complementary control inputs, not just enables.